The present invention relates to downhole fishing and drilling operations, or removing obstructions to a drilling line when such a line becomes lodged or otherwise stuck in a well bore. Conventional means of downhole retrieval are dubious, and usually involve attempting to actuate the entire work string in the hope of dislodging it or removing an obstruction. Often this is unsuccessful either because the work string cannot jar loose the obstructions, or adequate motion cannot be effected in the well bore. Consequences of this failure to remove the obstruction can be failure of the well to produce at all or in part, also, current methods of removing obstructions can result in line breakage, both of which result in having to relocate the drilling operation, which necessarily involves lost time and money.
The present invention is able to attempt to actuate a lodged object in the path of the drilling path without moving the work string, which results in reduced trauma and friction and prevents work hardening of the work string. The tool can also have various other applications, such as drilling, retrieving or driving other tools that may be attached to it, or in any application, down hole or otherwise, that may require such a jarring action.
One objective of this invention is to provide a device capable of maintaining tensile force on a drilling work string while dislodging an object that may be interfering with the well operation.
Another objective of the invention is to provide a device that is more efficient at dislodging obstructions interfering with well operations.
Still another objective of the invention is to provide a device that can be placed into any confined space and perform a jarring action, or drive other tools that require linear input.
Other objects and advantages of this invention shall become apparent from the ensuing descriptions of the invention.
According to the present invention, the down hole jar tool is a tool used to apply jarring forces to objects that may be obstructing the path of a down hole, or above-ground operation that requires a repetitive jarring action to dislodge or remove such objects. The tool is used by providing a linear input to a mandrel portion that draws back against a compressible unit of predetermined resistance until a releasing means abruptly releases the mandrel portion. The mandrel portion then rapidly moves in the direction of the linear input until it encounters a stationary anvil, which produces the desired jarring action. This tool may also be combined with accelerators and/or valves, as well as other tools, to create a more substantial jarring impact.